Hand-held gripping devices for picking up and gripping objects have been known for years and typically employ a jaw portion and a handle portion spaced apart by a central portion. Such “grippers”, “reachers” and “grapsers” typically have fixed-length central portions, although some have two part construction that permits a pivot point around the central portion of the device so that it can be stored more easily, and still others have telescoping portions to facilitate adjustable-length central portions.
In other related fields, such as surgery, dentistry and orthodontia, professionals often have a desire to reach interior portions of a person's anatomy to grasp objects, tissue, etc. Many prior art devices to achieve such objectives are linear with grasping jaws, while still others have a flexible portion that facilitates some angular adjustments. Such tools, however, are often complicated in terms of construction, often employing rails and jointed connections that rotate relative to each other to facilitate desired flexibility of the tool along at least an extent thereof. A simpler, cost effective, light weight and versatile tool is therefore desired that can facilitate such professional's procedures involving reaching into interior portions of a person's anatomy to grasp objects, tissue, etc.
Ischemic strokes can be caused by clots within a cerebral artery. The clots block blood flow, and the blocked blood flow can deprive brain tissue of its blood supply. The clots can be a thrombus that forms locally or an embolus that migrated from another location to the place of vessel obstruction. To reduce the effects of the cut off in blood supply to the tissue, time is an important factor. As stroke physicians say: “time is brain.” In particular, it is desirable to restore blood flow in as short of a period of time as possible. The cerebral artery system is a highly branched system of blood vessels connected to the interior carotid arteries. The cerebral arteries are also very circuitous. Medical treatment devices should be able to navigate along the circuitous route posed by the cerebral arteries for placement into the cerebral arteries. Stroke patients are more likely to recover if doctors quickly perform a minimally invasive procedure to restore blood flow to the brain and remove damaging clots, rather than using clot-busting drugs alone.
Findings recently presented at the International Stroke Conference in Nashville, Tenn., may change the way doctors handle many strokes, the fourth-leading cause of death in the U.S. They also show how important it is to immediately recognize stroke symptoms and get treatment. Currently, as many as 80 percent of patients with strokes caused by clots in the largest arteries in the brain die within three months or never regain independence.
Rapid removal of a thrombus (i.e., blood clot) after ischemic stroke can greatly reduce the risk of the loss of brain function. Conventional treatment for removing the thrombus includes pharmacology and surgery. Tissue plasminogen activator (tPA), a pharmaceutical, has been shown to help dissolve blood clots. Other drugs, including streptokinase and urokinase, have also been used. However, these drugs can take several hours to be effective.
Blood clots can also be mechanically removed using a system called Mechanical Embolus Removal in Cerebral Ischemia (MERCI®). It is believed that a system for thrombolysis that could easily be applied by an emergency room physician or physician's assistant would improve treatment and potentially save lives. Such thromboembolic disorders are typically characterized by the presence of a thromboembolus (i.e., a viscoelastic blood clot comprised of platelets, fibrinogen and other clotting proteins) which has become lodged at a specific location in a blood vessel.
In cases where the thromboembolism is located in a vein, the obstruction created by the thromboembolus may give rise to a condition of blood stasis, with the development of a condition known as thrombophlebitis within the vein. Moreover, peripheral venous embolisms may migrate to other areas of the body where even more serious untoward effects can result. For example, the majority of pulmonary embolisms are caused by emboli that originate in the peripheral venous system, and which subsequently migrate through the venous vasculature and become lodged with the lung.
In cases where the thromboembolus is located within an artery, the normal flow of arterial blood may be blocked or disrupted, and tissue ischemia (lack of available oxygen and nutrients required by the tissue) may develop. In such cases, if the thromboembolism is not relieved, the ischemic tissue may become infarcted (i.e., necrotic). Depending on the type and location of the arterial thromboembolus, such tissue infarction can result in death and amputation of a limb, myocardial infarction, or stroke. Notably, strokes caused by thromboembolic which become lodged in the small blood vessels of the brain continue to be a leading cause of death and disability, throughout the world.
In modern medical practice, thromboembolic disorders are typically treated by one or more of the following treatment modalities:
a) pharmacologic treatment wherein thrombolytic agents (e.g., streptokinase, urokinase, tissue plasminogen activator (tPA)) and/or anticoagulant drugs (e.g., heparin, warfarin) are administered in an effort to dissolve and prevent further growth of the clot;
b) open surgical procedures (e.g., surgical embolectomy or clot removal) wherein an incision is made in the blood vessel in which the clot is lodged and the clot is removed through such incision; and,
c) transluminal catheter-based interventional procedures wherein a clot removing/disrupting catheter having a clot capturing receptacle (e.g., a basket, coil, hook, etc.), or clot-disrupting catheter having a clot disrupting apparatus (e.g., an ultrasound probe or laser)) is percutaneously inserted and advanced through the patient's vasculature to a location adjacent the clot.
Each of the above-listed treatment modalities has its own set of advantages and disadvantages. For example, pharmacologic treatment has the advantage of being non-invasive and is often effective in lysing or dissolving the clot. However, the thrombolytic and/or anticoagulant drugs used in these pharmacologic treatments can cause untoward side effects such as bleeding or hemorrhage. Also, in cases where time is of the essence, such as cases where an arterial thromboembolism is causing severe tissue ischemia (e.g., an evolving stroke or an evolving myocardial infarction) the time which may be required for the thrombolytic drugs to fully lyse or dissolve the blood clot and restore arterial blood flow may be too long to avoid or minimize the impending infarction.
Open surgical thrombus-removing procedures can, in many cases, be used to rapidly remove clots from the lumens of blood vessels, but such open surgical procedures are notoriously invasive, often require general anesthesia, and the use of such open surgical procedures is generally limited to blood vessels which are located in surgically accessible areas of the body. For example, many patients suffer strokes due to the lodging of blood clots in small arteries located in surgically inaccessible areas of their brains and, thus, are not candidates for open surgical treatment.
Transluminal, catheter-based interventional procedures are minimally invasive, can often be performed without general anesthesia, and can in some cases be used to rapidly remove a clot from the lumen of a blood vessel. However, such catheter-based interventional procedures are highly operator-skill-dependent, and can be difficult to perform in small or tortuous blood vessels. Conventional baskets include Flatwire baskets, Helical baskets and Multi-wire baskets, each having their own disadvantages, such as flatwire baskets being unsuitable for capturing small calculi given the limited wires in such baskets providing too much space. Helical baskets must be drawn back over entrapped calculi to attempt to sweep a stone into the basket and its filaments prevent the entry of large calculi. All such baskets require a body to enter within an extractor sheath with the cage in a retracted position. Accidental escapes of such baskets is common and damage to the adjacent tissue sometimes occurs during the treatment. There is a need to solve the problem of reliable capturing, immobilization and holding of calculi and thrombus, irrespective of their size.
In addition to thrombus retrieval procedures, medical retrieval devices are often utilized for removing organic material (e.g., blood clots, tissue, and biological concretions such as urinary, biliary, and pancreatic stones) and inorganic material (e.g., components of a medical device or other foreign matter), which may obstruct or otherwise be present within a patient's body cavities. For example, concretions can develop in certain parts of the body, such as in the kidneys, pancreas, and gallbladder. Minimally invasive medical procedures are used to remove these concretions through natural orifices, or through an incision, such as during a percutaneous nephrolithotomy (PNCL) procedure. Further, lithotripsy and ureteroscopy, for example, are used to treat urinary calculi (e.g., kidney stones) in the ureter of a patient. Known medical retrieval devices are complex in structure, requiring many components and labor-intensive manufacturing processes, and many do not provide controls for varying the size of the retrieval end of the device.
Thus, there exists a need for the development of a new transluminally insertable, clot-capturing type embolectomy system, device and method to rapidly and selectively remove blood clots or other matter from small, delicate blood vessels of the brain, so as to provide an effective treatment for evolving strokes and other thromboembolic disorders.